Special tips:The color of blow case may be varied, you may receive item with black or red carry case, it won't affect item function. DO NOT USE IMPACT DRIVER! Caution: A compressed spring can inflict bodily injure, always wear safety glasses and gloves; Instructions: 1. lubricate both main shafts with oil; 2. Align the hooks with the safety pins backed off so the hooks will fit over the spring; 3. Position both set of hooks 180 a part, opposite each other; 4. Push safety pins in the lock position on hooks; 5. Using a 3/4"or 19mm socket and ratchet turn the main shaft compressing the strut spring enough to safely remove the fastener nut holding the cartridge. This item is designed to compress many MacPherson Strut Spring sizes The broad spring contact and built in detent pins help to lock the spring into place for safer This Tools Strut Spring Compressor quickly and safely compresses the spring for easy Replacement of the strut cartridge or strut assembly repair. The hooks are forged and the center screw is hardened for long life.